I have a '65 coupe (327ci/350hp w/AC)that I purchased recently and I want to change the oil. What should I put in? I have read a few posts here for newer models but nothing for mid-years. Should I get the type that was "stock" out of the factory or go synthetic?

 

Personally, I use Castrol GTX. Valvoline is a good oil too. I avoid Pensoil products. I have found parafin (wax) buildup under the valve covers of cars that used it over a period of time. It just holds onto crud that will eventually come loose and go back into your oiling system.
Just my $0.02 worth.

 

I also have a 65 and I run diesel oil like Shell Rotella Dino. The important thing is to make sure it has the additive c1-4 in it. This is a superior anti-wear additive for high mileage vehicles such as diesel trucks. I just changed my oil in my 327 350hp with 102k miles. I used Motorcraft 15w40 diesel. Five quart jug was 10 dollars at Advance Auto.

 

Hi sroffers65and welcome to the forum, I use conventional 30 w all year, it rarely gets below 40 degrees here and if it is the car is garaged so thats my choice. Enjoy your new ride, PG.